Abby Brewster: A darling lady in her sixties who poisons elderly men. Abby is the sister of Martha and an aunt to Teddy, Jonathan, and Mortimer.
The Rev. Dr. Harper: Minister and father of Elaine
Teddy Brewster: Nephew of Abby and Martha Brewster, Teddy is a man in his forties who thinks that he is Theodore Roosevelt.
Officer Brophy: A police officer
Officer Klein: A police officer
Martha Brewster: A sweet elderly woman with Victorian charm who poisons elderly men, Martha is the sister of Abby and an aunt to Teddy, Jonathan, and Mortimer.
Elaine Harper: An attractive girl in her twenties and Mortimer’s fiancee, Elaine is the daughter of the Rev. Dr. Harper. She is surprisingly wise in the ways of the world for a minister's daughter.
Mortimer Brewster: Nephew of Abby and Martha, Mortimer is a drama critic who is engaged to Elaine. He is a nice man who cares for his aunts.
Mr. Gibbs: A man who wishes to rent a room from the Brewster sisters
Jonathan Brewster: Nephew of Abby and Martha Brewster, Jonathan is a psychopath who has had plastic surgery and now looks like Boris Karloff.
Dr. Einstein: A plastic surgeon and an alcoholic who is in his fifties, Dr. Einstein has changed Jonathan's face three times.
Officer O'Hara: A police officer, O’Hara is a would-be playwright who pesters Mortimer to read his play.
Lieutenant Roony: A tough and dominating police officer
Mr. Witherspoon: The superintendent of Happy Dale Sanitarium